Switched capacitor DC-DC power converters are known in the art and have been utilized in various types of portable communication devices such as head-wearable hearing devices. Switched capacitor DC-DC power converters are utilized to convert a DC input voltage from an energy or power source, such as a rechargeable battery, of the portable communication device into a higher or lower DC output voltage suitable for powering various types of integrated circuits and other active components. Switched capacitor DC-DC power converters possess certain attractive properties compared to their inductor-based counterparts—for example a relatively low level of EMI, because there is not stored energy in magnetic fields of inductors. Switched capacitor DC-DC power converters may have small size and high energy conversion efficiency. Different topologies of switched capacitor DC-DC power converters are capable of providing DC voltage step-up (i.e. boost) and DC voltage step-down (i.e. buck) with a topology dependent optimum voltage conversion ratio for example 1:2 or 1:3 step-up conversion and 2:1 and 3:1 step-down conversion.
Switched capacitor DC-DC converters are highly useful for powering head-wearable hearing devices where the compact dimensions of the housing or custom shell in conjunction with small battery capacity typically place severe constraints on size, power conversion efficiency and electromagnetic emissions of the power supply circuitry.
However, there remains a need in the art for multiple-output switched capacitor DC-DC converters with improved performance characteristics such as smaller dimensions and better adaptation to varying load conditions and varying DC input voltages. In particular, providing improved energy efficiency across a wide range of loads and a wide range of DC input voltages because the DC input voltage often varies considerably e.g. due to a varying charging state of a rechargeable battery source supplying the DC input voltage.